This document provides an overview of cell division and genetics. It discusses the two main types of cell division: mitosis, which produces somatic cells, and meiosis, which produces gametes or sex cells. The stages of the cell cycle, mitosis and meiosis are described in detail. It also introduces key genetics concepts such as genotype, phenotype, homozygous, heterozygous, dominant and recessive alleles.

1. Chapter 10 Cell Division & Genetics GEE Science Summer Remediation Mr. Nash Donnie Bickham Middle School Room 204

2. Cellular Reproduction Multicellular organisms are composed of two kinds of cells: Somatic Reproductive Within these cells matched pairs of chromosomes are called homologous chromosomes or homologues. Homologues are similar in size and carry the same kinds of genes, but are not identical. Pg. 182

3. Somatic Cells Contain two sets of chromosomes. Two sets of chromosomes is called: Diploid (2n) Make up almost all cells in an organism. Of the two sets of chromosomes, one set comes from the mother and one set from the father. Pg.182

4. Mitosis and the Cell Cycle Mitosis is the reproduction of somatic cells. Often called cell division. Results in two diploid (2n) cells. Pg.182

5. Mitosis Some unicellular organisms reproduce asexually by mitosis. Asexual reproduction by mitosis produces a clone of the parent. Clones are genetically identical. Pg.182

6. Cell Cycle The cell cycle is the sequence of stages through which a cell passes between one cell division and the next. Contains six cycles or phases. Pg.183

7. Six Phases of the Cell Cycle Interphase  Prophase  Metaphase  Anaphase  Telophase  Cytokinesis Pg. 183

8. Interphase Most of the cell’s lifetime. DNA at this phase is long strands and is called chromatin. During the later stage, chromatin is duplicated in preparation for cell division. Pg.183

9. Prophase Chromatin condenses and coils to from rod shaped chromosomes. Each arm of the chromosome is called a chromotid and are attached at the centromere. Pg183.

10. Metaphase The nuclear envelope breaks apart. Spindles are completely formed. Pg183.

11. Anaphase Chromotids come apart. Chromotids are pulled by the spindle to each end of the cell. Pg.183

12. Telophase Last stage of mitosis. Chromosomes uncoil forming chromatin again. The nuclear envelope reforms. Pg.183

13. Cytokinesis The division of the cytoplasm. A cell plate forms within the cell dividing it into the two daughter cells. The cell plate becomes part of the new cell membranes. Pg.183

14. Meiosis and Sexual Reproduction Reproductive cells use Meiosis for cell division. Each cell will be haploid (n) or have only half the original chromosomes. Sex cells created by meiosis are called gametes. Pg.184

15. Meiosis Prior to meiosis gamete cells go through Interphase similar to somatic cells in mitosis. Meiosis occurs in two divisions: Meiosis I Meiosis II Pg.184

16. Meiosis I Prophase I Chromatin condenses into chromosomes. Homologues pair off. Same as in mitosis. Pg.184

17. Meiosis I Metaphase I Spindles form. Nuclear envelope disappears Same as in mitosis Pg. 184

18. Meiosis I Anaphase I Chromotids are pulled apart and pulled towards the spindles. Same as in mitosis Pg. 184

19. Meiosis I Telophase I Chromotids uncoil back into chromatin. Same as mitosis Pg.185

20. Meiosis I  Meiosis II After meiosis I, unlike mitosis, cytokinesis does not occur, but a stage called interkinesis. During interkinesis the chromatin is not duplicated like during interphase. Pg.185

21. Meiosis II Follows all of the stages of Meiosis I Prophase II Metaphase II Anaphase II Telophase II After completing Meiosis II, the gamete goes into Interphase to begin the process again. Pg.186

22. Genetic Expression DNA makes up the genes. Genes carry the traits that are inherited. Genotype: The gene make up for a particular trait. Phenotype: The visible expression of a genetic trait. Pg.187

23. Genetic Expression If an individual inherits two of the same alleles for a particular trait they are homozygous. This can be either dominant or recessive. If an individual inherits one dominant allele and one recessive allele, the individual is heterozygous. Pg.188